Apparatus for burning waste matter

ABSTRACT

Apparatus for burning waste matter in a combustion chamber comprising a feed bed with a plurality of stepped sections. Combustion air is introduced in the region of the transition from one stepped section to the next. The upper sides of the stepped sections are closed and the sections lie on an inclined frame which is connected to a vibrator.

iJnited States Patent [1 1 Sigg 41 APrARATus FOR BURNING WASTE MATTER[76] Inventor: Conrad Sigg, Ackermannstrasse 22,

Zurich, Switzerland [22] Filed: Mar. 30, 1972 [21] Appl. No.: 239,418

[30] Foreign Application Priority Data Apr. 29, 1971 Switzerland 6300/71[52] US. Cl. 110/8 R, 110/32 [51] Int. Cl. F23g 5/00 [58] Field ofSearch 110/7, 8, 15, 32, 33, 38, 74

[56] References Cited UNITED STATES PATENTS Drirka 110/38 Feb 12, 1974979,661 12/1910 Fortune 110/38 X 2,269,812 1/1942 Fulton 110/38 X3,212,465 10/1965 Cates, .lrv el :11 110/38 Primary Examiner-Kenneth W.Sprague Attorney, Agent, or FirmF1ynn & Frishauf [5 7 ABSTRACT Apparatusfor burning waste matter in a combustion chamber comprising a feed bedwith a plurality of stepped sections. Combustion air is introduced inthe region of the transition from one stepped section to the next. Theupper sides of the stepped sections are closed and the sections lie onan inclined frame which is connected to a vibrator.

8 Claims, 8 Drawing Figures PATENTEB FEB I 21974 SHEH 3 0F 3 APPARATUSFOR BURNHNG WASTE MATTER The invention relates to an apparatus forburning waste matter, such as refuse, rubbish, sludge and the like.

PRIOR ART In previously known systems for burning waste matter theburning material generally lies on a grate which has downwardly directedopenings through which the air for combustion reaches the burningmaterial. This grate usually consists of stationary parts and movableparts. Through a suitable reciprocating movement the burning material ismoved along the grate from an entry point to a discharge point.

The disadvantages of these known systems consist firstly in that, at theparts which move relative to one another, the moving grates have gapswhich enable material to fall through, while on the other hand they aresubject to considerable mechanical and thermal stressing and wear.Moreover another disadvantage consists in that the feed mechanism forthe burning material must be situated in the tire chamber and isconsequently subject to thermal stressing.

It is accordingly a first object of the invention to provide anapparatus or equippment for burning solid waste matter, pulpy orpastelike substances and sludge, which hitherto entailed the risk thatthey might pass between the grate openings.

Another object of the present invention is the provision of an improvedarrangement, which can be made mechanically very simple and can beproduced at a relatively low cost.

A further object of the present invention is to provide an apparatus inwhich the speed for burning of waste matter can be substantiallyincreased over that possible with prior art mechnism.

SUBJECT MATTER OF THE INVENTION A more specific object of the presentinvention is to provide an apparatus for burning waste matter comprisinga feed bed consisting of a plurality of hollow stepped sections, meansfor introducing combustion air in the region of the transition from onestepped section to the next, the upper sides of the stepped sectionsbeing closed, neighboring stepped sections lying against one another oroverlapping at their end faces to prevent the waste matter or theresidue thereof from falling therebetween.

The features of this invention together with further objects andadvantages thereof, may be best understood by reference to theaccompanying drawings, wherein:

FIG. 1 is a diagrammatic vertical section through a first embodiment ofan apparatus for burning waste matter. with stepped sections ofdifferent constructions,

FIG. 2 is a diagrammatic plan view of the apparatus shown in FIG. 1,

FIG. 3 is a diagrammatic front view of the apparatus of FIGS. 3. and 2,

FIG. 4 is a side elevation, partly in section, ofa modifled embodimentof an apparatus for burning waste matter. FIG. 5 is a plan view of theapparatus shown in FIG. 4,

FIG. 6 is a section on the line A-A in FIG. 5 and FIG. 7 is a section onthe line BB in FIG. 5,

FIG. 8 is a general view of a combustion installation.

The embodiment of the apparatus for burning waste material, such asrefuse, rubbish, sludge, illustrated in FIGS. 1 to 3, is incorporated ina combustion plant which may be provided with a multi-purpose burner. Acombustion plant of this kind may however also be used for burningplastics materials, or for the cremation of animal corpses. It has afeed bed with a plurality of hollow stepped section 1a, 1b, 1c, whichare closed at the upper side 4 and are disposed like a staircase. Thesestepped sections are fastened rigidly on a vibrating frame 2. The wastematerial to be burned is poured onto the uppermost step 1a of the feedbed, and during burning passes downwards from step to step in the formof burning material or a tire bed. The required air for combustion isfed from below the stepped sections through passages and passes outthrough slots 3 on passing from one stepped section to the next. Theseslots 3, or outlet nozzles, are situated directly at the height of theupper side 4 of the next following lower stepped section.

In FIG. 1 three different kinds of stepped sections 1a, lb and 1c areillustrated. As a rule, however, only a single kind of stepped sectionis used in one combustion apparatus. The inclination of at least a partof the upper side 4 of the individual steps is oppositely directed tothe inclination of the frame 2 which is preferably about 15. In order toprevent waste material or the products of combustion from fallingthrough at the divisions between the end faces of neighboring stepsections 1a, lb, 10, the stepped sections are joined tightly to oneanother either by a transverse bar 5 or by being'pulled close to oneanother by means of screws 6 or other fixing elements.

The individual stepped sections are hollow and, as the air forcombustion enters from the lower side, heat exchange takes place. Adeflector 9 projects into the interior of the cavity of the steppedsections and deflects the current of air, while at the same timeenabling the air to flow in substantially without turbulence andpractically parallel to the upperside 4 of the stepped sections.

The steps lb andlc have an upper side 4 with ribs. In the case of thecombustion of liquid or paste-like waste matter it is however convenientfor a transverse bead 19 to be provided at the outer end of the steppedsections (FIG. 4). The deflector 9 is so shaped that over at least partof its length it is situated at a higher level than the upper surface 4of the next lower stepped section, in order to prevent a return flow.

Upwardly projecting guide plates 7, which are pro-- vided on one side ofthe stepped sections, form a flat wall, while guide plates 8, which areprovided on the other side, have a staircase-like stepped profile.Moreover, additional air for combustion may optionally pass out throughgaps 10 between the guide plates.

In the alternative embodiment illustrated in FIGS. 4 to 7, the wastematerial passes gradually from an inlet 12 to an outlet 13, from whichthe residue, ashes or slag are removed. A feed bed 11 is provided with avibrator 14, by which it is kept in continuous or intermittent movement,so that the burning material moves downwards through the action of thevibrations. The individual steps are slightly inclined towards theoutlet 13.

Vertical side walls 16, which laterally bound the burning material,converge in the direction of movement, the width of the feed beddecreasing in the direction of the outlet I3 in the embodimentillustrated in FIG. 5. Since the height of the layer of waste materialdecreases as the combustion process progresses, it is convenient for thewidth of the feed bed to decrease in the direction of the outlet 13.

When special circumstances exist, however, it is also possible for thewidth of the feed bed to increase in the direction of movement, that isto say in the downward direction.

In order to guide the burning material, which is moving downwards in thedirection of movement through the action of the vibrations, towards thelongitudinal centre, there are provided on the upper side 20 of steppedsections ribs 18 which are likewise convergent in accordance with thevarying width of the feed bed, as can be seen in FIG. 5.

From FIG. 6 and 7 it can be seen that not only the width but also thecross-sectional shape of the feed bed vary in the direction of movement.Near the inlet 12, the upper side of the stepped sections 15 extendssubstantially horizontally and straight, viewed in crosssection, whereasin the direction of the outlet 13 it gradually merges into a curved,concave shape.

It is preferable for the stepped sections to be made of a compactedrefractory mineral material which sets chemically. Ceramic compositionswhich have good resistance to acids have been found satisfactory ascompacted materials. It is also possible for the individual steppedsections to be formed by producing a skeleton of metal which is enclosedin or lagged with a compacted material.

The two side walls 16 and the stepped sections 15 are preferably in onepiece.

The material to be burned is advanced continuously through the action ofthe vibrator. Brief interruptions, or the throttling of the vibrations,are also possible. Furthermore the vibrator may be operated with avariable amplitude or frequency in order to achieve slower or fasteradvance of the burning material. In addition it is also possible for thevibrator to be fastened pivotally, so that its vibrations act more inthe direction of advance of the burning material or, for the purpsoe ofthrottling the advance, more in the vertical direction.

The stepped sections la, 1b, 1c and the side walls 16 are convenientlymade of heat-resistant cast iron, steel, or cast alloy steel.

Instead of the gap between two neighboring step sections being disposedat the step riser, a construction would also be possible in which thedeflector 9 is in one piece with the part la or lb or Be following inthe direction of movement. Here again the highest point of thisdeflector 9 should be at a higher level than the following upper side 4or of the cross-rib 19, where the latter is provided.

FIG. 8 shows a schematic illustration ofa combustion installation with acombustion chamber 21. Solid waste is entered in the inside of thecombustion chamber 21 by transporting means 25 and sludge or the like isentered by a pipe 24 at a predetermined rate. Fuel gas pipes 26 and airpipes 36 are discharging into burners 28 so that a high temperature isgenerated in the combustion chamber 21. The waste or sludge forms aburning fluidized bed 22 on the stepped sections 23, which correspondsto the step sections 1a, lb or 10 of FIG. 1. To assist the burningprocess air is blown by a blow-er or fan 39 via a pipe 29 from theunderside of the frame to the outlet nozzles or slots 3 of the steppedsections. The ash 30 is collected in a fly ash conveyor 31. Theuncleaned exhaust gas leaving the combustion chamber 21 is collected bya flue or smoke gas cap 27 and passes then through a heat exchanger 28and a multi-cyclone 33 and is then guided to an induced draught fan 34into a chimney exhaust 35.

It will be readily apparent to those skilled in the art that a widevariety of such apparatuses might be provided without departing from thespirit of this invention.

I claim:

1. Apparatus for burning waste matter comprising;

a longitudinally inclined feed bed carrier provided with means forvibrating said carrier;

a plurality of hollow step-forming sections mounted in fixed positionstransversely on said carrier so as to present a support surface for saidwaste matter that is substantially continuous except for openings in therisers of said stepped surface;

said step-forming sections being shaped so that, as disposed on saidcarrier, their forward edges are lower than their junctions with thebottom of the riser of the next higher step-forming section and shapedso that openings are formed in the risers communicating with theinterior of said sections and so that the floor of said openings risesrearwardly so as to oppose flow of waste matter from the stepped surfacerearwardly into the openings;

means for introducing combustion air into the space between said carrierand said stepped sections for supplying said air through said riseropenings to the combustion of said waste matter, and

retaining side walls mounted in fixed positions on said carrier andextending above said stepped surface on either side to prevent sidewaysescape of said waste matter.

2. Apparatus according to claim 1, in which the width of the feed beddecreases in the direction of movement of the burning material,converging longitudinal ribs being provided on the upper side of thefeed bed.

3. Apparatus according to claim 1, in which the cross-sectional shape ofthe feed bed varies in the direction of movement of the burningmaterial, the support surface of the feed bed being transversely flat atthe top and merging at the bottom into a concave shape.

4. Apparatus according to claim 1, in which the stepped sections aremade at least partly of a compacted refractory mineral ceramic material.

5. Apparatus for burning waste matter as defined in claim 1, in whichsaid step-forming sections have an interior shape such that saidcombustion air streams out of said openings in a direction substantiallyparallel to the top surface of the adjacent step.

6. Apparatus for burning waste matter as defined in claim 1, in whichsaid step-forming sections have a lower portion shaped so as to meettightly and to extend the surface of the next lower section and therebyto provide the rearwardly rising floor for said riser openings andfurther shaped so as to provide a deflector for causing the combustionair supplied to said openings to stream substantially parallel to thesurface of said next lower step.

7. Apparatus for burning waste matter as defined in claim 1, in whichsaid step-forming sections overlap, so that the overlapped portion of alower section provides 6 stepped form providing shallowdownstream-facing risers having additional combustion air orfices, andin which means are provided for supplying a flow of air through saidadditional orfices.

1. Apparatus for burning waste matter comprising; a longitudinallyinclined feed bed carrier provided with means for vibrating saidcarrier; a plurality of hollow step-forming sections mounted in fixedpositions transversely on said carrier so as to present a supportsurface for said waste matter that is substantially continuous exceptfor openings in the risers of said stepped surface; said step-formingsections being shaped so that, as disposed on said carrier, theirforward edges are lower than their junctions with the bottom of theriser of the next higher stepforming section and shaped so tHat openingsare formed in the risers communicating with the interior of saidsections and so that the floor of said openings rises rearwardly so asto oppose flow of waste matter from the stepped surface rearwardly intothe openings; means for introducing combustion air into the spacebetween said carrier and said stepped sections for supplying said airthrough said riser openings to the combustion of said waste matter, andretaining side walls mounted in fixed positions on said carrier andextending above said stepped surface on either side to prevent sidewaysescape of said waste matter.
 2. Apparatus according to claim 1, in whichthe width of the feed bed decreases in the direction of movement of theburning material, converging longitudinal ribs being provided on theupper side of the feed bed.
 3. Apparatus according to claim 1, in whichthe cross-sectional shape of the feed bed varies in the direction ofmovement of the burning material, the support surface of the feed bedbeing transversely flat at the top and merging at the bottom into aconcave shape.
 4. Apparatus according to claim 1, in which the steppedsections are made at least partly of a compacted refractory mineralceramic material.
 5. Apparatus for burning waste matter as defined inclaim 1, in which said step-forming sections have an interior shape suchthat said combustion air streams out of said openings in a directionsubstantially parallel to the top surface of the adjacent step. 6.Apparatus for burning waste matter as defined in claim 1, in which saidstep-forming sections have a lower portion shaped so as to meet tightlyand to extend the surface of the next lower section and thereby toprovide the rearwardly rising floor for said riser openings and furthershaped so as to provide a deflector for causing the combustion airsupplied to said openings to stream substantially parallel to thesurface of said next lower step.
 7. Apparatus for burning waste matteras defined in claim 1, in which said step-forming sections overlap, sothat the overlapped portion of a lower section provides the rearwardlyrising floor for said riser openings and also a deflector for causingthe combustion air supplied to said openings to stream substantiallyparallel to the top surface of said lower section.
 8. Apparatus forburning waste matter as defined in claim 1, in which at least one ofsaid side walls is of stepped form providing shallow downstream-facingrisers having additional combustion air orfices, and in which means areprovided for supplying a flow of air through said additional orfices.